It is clear that motor vehicles will in the future need more and more electrical energy to operate under optimal conditions in order to comply with new legislation that will come into force in the next few years, in particular concerning pollution.
The invention proposes a rectifier device that contributes to these objectives and which in particular improves the efficiency and the output of an alternator by reducing rectifier losses and iron losses in the stator and the rotor. The device proposed by the invention also reduces magnetic noise from the alternator by preventing non-linear switching of low-level current.
It is standard practice to use for rectifying the output voltage of a motor vehicle multiphase alternator Graetz full-wave rectifier bridges comprising switching circuits controlled synchronously with the voltages of the various phases of the armature.
In this connection reference is made to patent applications EP-665.637 and EP-762.596.
The switches used are generally enriched N-channel insulated gate transistors (usually called MOSFET). Compared to Graetz bridges using diodes, bridges using switches have the advantage of reducing the direct voltage drop at their terminals.
However, a rectifier bridge of the above kind for motor vehicles operates in an electrical environment subject to very high levels of interference and this can lead to irregularities in the controlling of the switches.
An object of the invention is to provide a rectifier device that mitigates these drawbacks.
The device proposed by the invention also has the advantage of being very low in cost and of being capable of withstanding high temperatures.